Ok, I'll bring up the dreaded words, "Self esteem," the most successful students have a great deal of it. They are not afraid to take up a challenge, especially one where they know the expectations and how to meet them.
Now how do kids develop self-esteem? Not by stars, stickers, and smiley faces alone-at least not for most. Nope, starts at home. Give the kids meaningful jobs, including but not limited to keeping their rooms pestilence free. Reward them for completing truly significant jobs, done well. For little children, toddlers, it would be placing their toys in a bin/basket before going to bed. Picking out their clothes and putting dirty ones in basket. Brushing their teeth. Of course, the parents have to make it possible by providing the easy access to these activities and a schedule for the child's day. They can't do it themselves.
By kindergarten kids can help with dinner by setting table, pour cereal, make salads with prepared ingredients, make their beds, (if the tucking in of sheets doesn't get parents out of whack), rake leaves, pick up toys, the list goes on. They are very good at polishing/dusting furniture-if shown how to do so. They may not be able to get the dining room table top or the credenza, but they sure can get all the legs and drawer fronts.
By 3rd/4th grade kids can entertain younger siblings, (with adult close at hand); do all the above; shovel snow within reason; rake and put leaves in bag. Make their own lunch for school; bring home correspondence from and to school, etc.
Middle schoolers can do all above plus watch younger children; cut grass; should be responsible for all homework and scheduling of activities, asking for assistance when necessary. Their parents should be able to give them an amount to purchase clothes and they should be able to adjust their choices to fit the budget. If they breach trust, they should be able to site a just punishment-often being harder than their parents would have been.
That's how one avoids an over-indulged child.
I know what Samson is referring to. Some highly able students fail to work. A little talking with them finds that they have every electronic gizmo known to me. They have a cleaning person so no, they don't make a bed, take out trash. They have landscaper to care for lawn and snow removal. You catch the drift.